In accordance with rapid aging of the population in recent years, there are increasing needs for welfare assistive devices that support caring of aged persons in the field of welfare. The most burdensome work in the field of caring is moving a cared person or adjusting the posture of the cared person. Much attention is paid to care-oriented power assisting devices that alleviate a load applied on the muscle force of a caregiver who makes such movement or adjustment.
For example, Document 1 discloses a care-oriented power assisting device that functions with use of an air pressure actuator having a light weight and a small size. Further, Document 2 discloses a power assisting instrument with a downsized structure that alleviates a load applied on human muscles. Other examples include HAL manufactured by CYBERDYNE Inc.
These power assisting devices are also effective for muscle training with alleviated or added loads on muscles in the field of sports engineering or rehabilitation engineering.
In order to develop a new method for evaluating athletic abilities or a new rehabilitation method, much studies have been made in the field of sports engineering or rehabilitation engineering as to estimation of muscle activities of humans in motion. For example, Document 3 discloses a technique for estimating the muscle force of a living body. In the technique, athletic properties of a subject who operates an exercise device are measured, and inverse analysis is used. Examples of commercially available software for such estimation include “ARMO” that is a 3D muscle simulator manufactured by Gsport Inc., and “SIMM” that is a musculoskeletal model of a whole body manufactured by Musculographics Inc.
It is desirable that a power assisting device worn by a caregiver allows individual regulation of loads applied on respective muscles in consideration of muscular properties, in order that unnatural loads are not applied on the caregiver.
Further, in order to increase a rehabilitation effect for a handicapped person, it is desirable to classify individual muscles into muscles on which loads are to be applied and muscles on which loads are not to be applied, and regulate loads applied on the individual muscles so as to selectively assist the muscles on which loads are not to be applied. Equally, it is desirable to selectively apply loads on the muscles on which loads are to be applied in muscle training.
However, none of Documents 1, 2, and 3 discloses a technique for regulating loads on individual muscles while a power assisting device assists a predetermined motion. For example, the power assisting device disclosed in Document 1 has rotatable joints at positions corresponding to human joints and has actuators for rotating the joints. However, Document 1 does not disclose a method for regulating the driving forces of the actuators so that individual muscles generate respective muscle forces of desired values.
Further, the power assisting instrument disclosed in Document 2 determines the amount of an assist power by causing a sensor section to measure an acting force received by a person when the person acts. However, Document 2 does not disclose a method for regulating individual muscle forces to be generated by respective muscles when determining the amount of assist power. The same can be said about HAL manufactured by CYBERDYNE Inc.
The method disclosed in Document 3 for measuring properties of a muscle force of a living body is a method for measuring properties of a muscle force necessary for a predetermined motion in a case where the person is in a normal state, that is, where the person does not wear a power assisting device. The method is not for controlling the driving force of the power assisting device so that individual muscles generate desired muscle forces in a case where the person wears the power assisting device. The same can be said about “ARMO” that is the 3D muscle simulator manufactured by Gsport Inc., and “SIMM” that is the musculoskeletal model of a whole body manufactured by Musculographics Inc.
[Document 1]
    Japanese Unexamined Patent Publication No. 2000-51289 (Tokukai 2000-51289; published on Feb. 22, 2000)[Document 2]    Japanese Unexamined Patent Publication No. 2004-105261 (Tokukai 2004-105261; published on Apr. 8, 2004)[Document 3]    Japanese Unexamined Patent Publication No. 1995-313495 (Tokukaihei 7-313495; published on Dec. 5, 1995)